There has been a constant need for safety devices in firearms to prevent their accidental discharge or use by unauthorized individuals. To this end, various locking devices and mechanisms have been developed to prevent operation of the firearm. Various devices are available which connect to the trigger housing of a firearm and lock the housing against access to the firearm trigger. With such devices, the firearm is not disabled by the locking mechansim but is simply rendered inoperable while the locking mechanism is in place on the trigger guard. Such mechanisms, since they are removable from the firearm, may be easily misplaced and lost.
In addition, devices are known for use in magazine type firearms, particularly those which employ a box type magazine, which fit into the magazine receiver in place of the normal magazine and which are locked in place. Such devices are similar to the trigger locks in that they merely render the weapon inoperable for use with a magazine. They may still permit the weapon to be used in a single shot fashion where each round is manually loaded. Also, like the trigger locks, since these devices are fully removable, they may be misplaced or lost, thus rendering them unusable.
It is therefore desirable to provide some form of locking mechanism which may be integrated with a firearm at manufacture or which may be readily retrofitted to existing firearms and which remains with the firearm at all times. It is also desirable to provide a simple locking mechanism which disables the firearm completely when locked but does not interfere with the normal operation of the firearm when the mechanism is unlocked. Furthermore, it is desirable to provide a locking mechanism which locks the firearm in such a manner that disassembly of the firearm in order to remove the locking mechanism is not possible while the firearm is locked. The prior art includes several attempts which have been made to fill the need for such a device.
U.S. Pat. No. 633,939 to Ackerman discloses a locking device for shotgun break levers. Operation with a key selectively moves a pin into position within a socket in the break lever to lock the lever in position and thereby prevent the weapon from being opened. This mechanism does not prevent the weapon from being discharged in the event that the lock is set after the weapon is loaded.
U.S. Pat. No. 2,945,316 to Mulno discloses a safety lock for firearms in which a threaded means is operated by a removable key to be advanced or retracted so as to engage a part of the firing mechanism of the weapon in which it is installed. The device includes a structure to prevent operation by other than the proper key.
U.S. Pat. No. 3,462,869 to Wallace discloses a key operated safety device for firearms which places a cylinder lock in an opening in the hammer of the weapon. In order to release the lock and permit operation of the weapon the lock must be substantially withdrawn from the weapon.
U.S. Pat. No. 3,553,877 to Welch discloses a firearm safety device which makes use of a key lock mechansim and an actuator arm to shift a lever into a position where it prevents movement of the weapon's integral safety mechanism from a "safe" to a "fire" position. This device operates through interfacing with the complex trigger mechanism.
U.S. Pat. No. 3,673,725 to Cravener discloses a locking arrangement using a key device which selectively positions a hammer rod obstruction into the rearward path of the weapon's hammer. The obstruction prevents the hammer from being withdrawn. In alternative embodiments, the device operates to bind other moving parts of a firearm such as a safety release lever.
U.S. Pat. No. 3,735,519 to Fox discloses a locking device that prevents movement of the weapon's safety to a firing position. The lock includes a combination tumbler requiring that the proper combination of numbers be arranged to disconnect the lock and allow the sear to pivot away from the bolt, thereby enabling the bolt to move. This device has a complexity level which renders it appropriate only for installation at the time of the weapon's manufacture inasmuch as it engages the trigger mechanism.
U.S. Pat. No. 3,882,622 to Perlotto discloses a locking device to lock a weapon safety latch mechanism into position. This device requires extensive tooling to fit it into place and is more suited to integral manufacture with the weapon, rather than as a retrofit.
U.S. Pat. No. 4,136,475 to Centille discloses a safety device for firearms which causes a locking pin to be shifted into position to prevent operation of the firearm trigger. The device makes use of a rack and pinion gear linkage by which the locking pin is movable into engagement with the trigger seat.
U.S. Pat. No. 4,261,127 to Karkkainen discloses a safety lock for firearms having a wooden stock with a pistol end wherein the lock is mounted in the pistol end and employs a flexible shaft for transmitting the movement of the tumbler to a member which engages and blocks the operation of the trigger mechanism of the weapon. Such flexible shafts are often susceptible to binding thus rendering the mechanism unreliable nor does this mechanism prevent disassembly of the weapon.
U.S. Pat. No. 5,081,779 to Pack discloses a safety lock for firearms which includes a hammer pin which is in constant contact with the hammer of the firearm and which can be locked into position by aligning a lock surface with a plunger. If the hammer pin jams or binds in any way it may prevent operation of the lock or the weapon even when the mechanism is unlocked.
The prior art presents locking mechanisms which are complex, which may be subject to interference or jamming and which are therefore unreliable. Others do not lend themselves to ease of use or installation either during manufacture or as a retrofit to existing weapons. Furthermore, the prior art does not disclose a locking apparatus which both locks the weapon against use and prevents its disassembly in order to circumvent the locking mechanism. The need therefore remains for a simple, effective and reliable apparatus for locking firearms against unauthorized use in which the locking mechanism operates to prevent the movement of a key element in the firing mechanism of the firearm and which prevents disassembly of the firearm in order to circumvent the locking mechanism.